Light Out‐Coupling Enhancement of Blue Quantum‐Dot Light‐Emitting Diodes with Internal Diffraction Wrinkle Pattern

Highly efficient blue quantum‐dot light‐emitting diodes (QLEDs) are still a challenge for displays and solid‐state lighting due to light trapping in a device. Herein, an internal diffraction wrinkle pattern is used to demonstrate a spectrum‐independent enhancement strategy for light out‐coupling. The optimized device with wrinkle pattern shows a peak external quantum efficiency of 15.25% and a maximum luminance of 13 134 cd m−2, and the enhancement of those is 23% and 28%, respectively. The improvement of device performance can be attributed to the extraction of waveguide light by the internal wrinkle pattern used as a diffraction grating. Moreover, simulation also shows that wrinkle pattern is an attractive option to improve the performances of blue QLEDs.